Condensation polymers for antimicrobial applications

ABSTRACT

A number of cationic antimicrobial polymers have been synthesized by a condensation polymerization in bulk. The initial polymer formed has backbone tertiary nitrogens, which are subsequently quaternized using a suitable quaternizing agent (e.g., alkyl halide). The cationic polymers include polyamides, polycarbonates, polypolyureas and polyguanidiniums having a cationic repeat unit comprising the quaternary ammonium nitrogen as a backbone nitrogen. The cationic polymers can be active against Gram-negative, Gram-positive microbes, and/or fungi.

This invention was made under a joint research agreement betweenInternational Business Machines Corporation and the Agency For Science,Technology and Research.

BACKGROUND

The present invention relates to condensation polymers for antimicrobialapplications, and more specifically, to cationic forms ofpolycondensation polymers for topical antibacterial use.

Antimicrobial agents are commonly used in personal care products toinhibit microbial growth and infections therefrom, and productdecomposition. Most antimicrobial agents used in these products aresmall molecules, including anilides (e.g., triclocarban), bis-phenols(e.g., triclosan), biguanides (e.g., chlorhexidine) and quaternaryammonium compounds (e.g., cetylpyridium chloride and cetrimide). Amongthem, triclosan is one of the most extensively used compounds. Triclosanis present in more than 50% of consumer products including soap,deodorant, toothpaste, mouth wash, cosmetics (e.g., Garden Botanika®Powder Foundation, Mavala Lip Base, Jason Natural Cosmetics and Movate®Skin Litening Cream HQ), cleaning supplies, kitchen utensils, children'stoys, bedding, socks, shoes and trash bags. It is effective againstGram-positive bacteria, while it has little activity against P.aeruginosa (Gram-negative bacteria) and molds. At high concentrations,it is biocidal with multiple cytoplasmic and membrane targets. However,at low concentrations, it is bacteriostatic by inhibiting fatty acidsynthesis. On the other hand, triclosan has cumulative and persistenteffects on the skin. It was found in human breast milk and urinesamples. At minimal concentrations of triclosan (<g/L) and chlorine(<mg/L), common household tap water levels, triclosan can degrade toform toxic derivatives, 2,4-dichlorophenol and 2,4,6-trichlorophenol.Moreover, in sunlight and wastewater chlorine treatment, it also formshighly toxic carcinogenic dioxin-like compounds. After use, it isdischarged into water. Triclosan was found in 85 out of 139 streams andrivers in 30 states in the US, and is toxic to aquatic species. It ispersistent in the environment, and was detected in sediments in a Swisslake as far back as the 1960s. Therefore, the use of triclosan inconsumer products will be banned in Europe and in the United Stateswithin 2 years.

Many strains of bacteria spores (e.g., Clostridium species),Gram-positive bacteria (e.g., mycobacteria) and Gram-negative bacteria(e.g., Pseudomonas aeruginosa (P. aeruginosa)) have intrinsic resistanceto the antimicrobial agents listed above. Moreover, these antimicrobialagents are not effective against biofilms. For example, Serratiamarcescens (S. marcescens) and Burkholderia cepacia (B. cepacia)biofilms were found in disinfectant chlorhexidine solution, P.aeruginosa biofilm in iodophor antiseptics and on the interior surfaceof polyvinyl chloride pipes used in the production of providone-iodineantiseptics. Overuse of these antimicrobial agents has led to drugresistance in microbes. Major concerns include cross-resistance andco-resistance with clinically used antimicrobial agents, which maypresent a potential public health risk.

Most small molecule antimicrobial agents do not physically damage thecell wall, but rather penetrate the cell wall and act on specificintracellular targets. Consequently, bacterial morphology is preserved,allowing bacteria to easily develop resistance. Antimicrobial peptides(AMPs) have been explored as an alternative. AMPs (e.g., magainins,alamethicin, protegrins and defensins) do not have a specific target inmicrobes. They interact with microbial membranes based on electrostaticinteraction, inducing damage to the microbial membranes by forming poresin the membranes. The physical nature of this action prevents microbesfrom developing resistance to AMPs. Although efforts have been made todesign synthetic peptides with various structures over the last twodecades, high manufacturing cost has limited their application inpersonal care products.

A number of cationic polymers that mimic the facially amphiphilicstructure and antimicrobial functionalities of peptides have beenproposed that can be more easily prepared at low cost and on large scalecompared to peptides. For example, antimicrobial polynorbornene andpolyacrylate derivatives, and pyridinium copolymers were synthesizedeither from amphiphilic monomers (homopolymers) or from cationic(hydrophilic) monomer and hydrophobic comonomer (random copolymers).However, most antimicrobial polymers reported in the literature arenon-biodegradable and/or require several steps of synthesis. With thehigh volume of poorly degradable single-use consumer products alreadydestined for landfills, the problem would be exacerbated by the additionof non-biodegradable antimicrobial materials that destroy bacteria andfungi responsible for slow landfill degradation.

A number of biodegradable cationic polycarbonates having high potencytowards pathogenic microbes and low toxicity. These cationicpolycarbonates degrade in aqueous solution especially in an alkalineenvironment which is often found in consumer care products. On the otherhand, the synthesis of polycarbonates requires several steps likemonomer synthesis, ring-opening polymerization and post-quaternization,which can translate into high consumer prices.

Currently, biodegradable, safe and cost-effective antimicrobial agentsare needed for use in personal care products that can killmultidrug-resistant bacteria and fungi, remove biofilms, and preventdrug resistance.

SUMMARY

Accordingly, a cationic polymer is disclosed, comprising:

a cationic repeat unit of formula (1):

wherein

W′ is a single bond or a divalent linking group having a structure*—C(═O)-L′-*, wherein L′ is divalent radical comprising 1-20 carbons andL′ is linked to carbon 1,

L′ is a divalent radical comprising 1-20 carbons,

L^(a) and L^(b) are independent divalent hydrocarbon groups comprising2-20 carbons, and

Q′ is a divalent radical comprising a positive-charged nitrogen which iscovalently bonded to 4 carbons, and

adjacent repeat units of the cationic polymer are covalently linked in ahead-to-tail arrangement, wherein nitrogen labeled 2 is designated atail and W′ is designated a head.

Also disclosed is a method of killing a microbe, comprising contactingthe microbe with an above-described cationic polymer.

Also disclosed is an antimicrobial composition comprising anabove-described cationic polymer and at least one other chemicalcomponent.

The above-described and other features and advantages of the presentinvention will be appreciated and understood by those skilled in the artfrom the following detailed description, drawings, and appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a ¹H NMR spectrum of cationic polymer P48a.

FIG. 2 is a ¹H NMR spectrum of cationic polymer P48b.

FIG. 3 is a ¹H NMR spectrum of cationic polymer P49a.

FIG. 4 is a ¹H NMR spectrum of cationic polymer P49b.

FIG. 5 is a bar graph showing the killing efficiency of cationicpolymers P32c and P32d against Staphylococcus aureus (S. aureus) atpolymer concentrations of 0.5MIC, 1.0MIC and 2.0MIC.

FIG. 6 is a bar graph showing the killing efficiency of cationicpolymers P32c and P32d against Pseudomonas aeruginosa (P. aeruginosa) atpolymer concentrations of 0.5MIC, 1.0MIC and 2.0MIC.

FIG. 7 is a bar graph showing the killing efficiency of cationicpolymers P32c and P32d against Candida albicans (C. albicans) at polymerconcentrations of 0.5MIC, 1.0MIC and 2.0MIC.

FIG. 8 is a pair of graphs showing the killing kinetics of cationicpolymers P32c and P32d at respective concentrations of 1.0MIC and 2.0MICagainst S. aureus.

FIG. 9 is a series of bar charts comparing the killing efficiency ofcationic polymers P48a and P49b at concentrations of 0.5MIC, 1.0MIC and2.0MIC against S. aureus, P. aeruginosa, and C. albicans.

FIG. 10 is a bar chart showing human dermal fibroblast (HDF) cellviability after a 6 hour treatment with various concentrations ofcationic polymers P32c, P32d, P48a, P48b, P49a and P49b.

DETAILED DESCRIPTION

The disclosed cationic polymers are biodegradable materials comprisingcationic repeat units having at least one quaternary nitrogen in thepolyamine backbone. For this reason, the cationic polymers are alsoreferred to herein as “polyamines”. The quaternary nitrogen is apositive-charged nitrogen covalently bonded only to carbons (3 or 4carbons), and is ionically associated with a negative-charged counterionX⁻. Preferably, X⁻ is a free ion, which is not directly or indirectlycovalently linked to the polyamine backbone. The polyamines comprisecationic repeat units having a backbone portion that preferably compriseamide, carbamate, and/or urea functional groups. The polyamines arewater soluble and can be highly active against Gram-positive microbes(e.g., S. aureus), Gram-negative microbes (e.g., Escherichia coli (E.coli), P. aeruginosa), and fungi (e.g., C. albicans). The polyamines canbe biocompatible, biodegradable, non-hemolytic, and non-cytotoxic atconcentrations above the minimum inhibitory concentration (MIC), and aretherefore attractive for a wide range of consumer products such as, forexample, cosmetics, skin lotions, and antibiotic drugs. The polyaminesare capable of forming ionic complexes with anionic materials, makingthem potentially useful as carriers for gene and/or drug deliveryapplications.

The term “biodegradable” is defined by the American Society for Testingand Materials as degradation caused by biological activity, especiallyby enzymatic action, leading to a significant change in the chemicalstructure of the material. For purposes herein, a material is“biodegradable” if it undergoes 60% biodegradation within 180 days inaccordance with ASTM D6400. Herein, a material is “enzymaticallybiodegradable” if the material can be degraded (e.g., depolymerized) bya reaction catalyzed by an enzyme.

A “biocompatible” material is defined herein as a material capable ofperforming with an appropriate host response in a specific application.

The polyamines are preferably linear homopolymers or linear randomcopolymers. Herein, a linear polymer has one polymer branch, and thebranch has two peripheral ends (i.e., two dangling ends, as in a segmentof a rope).

The cationic repeat units have a structure according to formula (1):

wherein

W′ is a single bond or a divalent linking group having a structure*—C(═O)-L′-*, wherein L′ is divalent radical comprising 1-20 carbons andL′ is linked to carbon 1,

L^(a) and L^(b) are independent divalent hydrocarbon groups comprising2-20 carbons, and

Q′ is a divalent radical comprising a positive-charged nitrogen which iscovalently bonded to 4 carbons.

Starred bonds (i.e., bond with an asterisk) represent attachment pointsfor a covalent bond, not methyl groups. An atomic center or group havinga starred bond (i.e., shown linked to an asterisk) means the atomiccenter or group is covalently bonded to another portion of the chemicalstructure.

When W′ is a single bond, the cationic repeat unit has a formula (1A):

and the polyamine backbone comprises a urea group. When W′ is*—C(═O)-L′-*, the polyamine backbone can comprise amide, carbamate,and/or urea groups.

The repeat units of the polyamines are linked in a head-to-tailarrangement. The nitrogen end is the tail (e.g., nitrogen labeled 2 offormula (1) is designated the tail), and the opposing end the head. Thehead of a given repeat unit can be linked to the tail of a differentrepeat unit or to a polymer chain end group. Likewise, the tail of agiven repeat unit can be linked to head of a different repeat unit or toa polymer chain end group.

When present, L′ can have any suitable structure. For example, L′ can bea divalent hydrocarbon group. Exemplary non-limiting divalenthydrocarbon groups include methylene, 1,1-ethylene, 1,2-ethylene,1,1-propylene, 1,2-propylene, 1,3-propylene, 1,1-butylene, 1,2-butylene,1,3-butylene, 1,4-butylene, 1,1-pentylene, 1,2-pentylene, 1,3-pentylene,1,4-pentylene, 1,5-pentylene, 1,2-cyclohexylene, 1,3-cyclohexylene,1,4-cyclohexylene, 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene.Accordingly W′ can have a structure that includes those of Scheme 1,wherein carbon 1 is linked to carbonyl carbon 1 of formula (1).

Other L′ groups include those of Scheme 2.

wherein n is an integer having a value of 1 to 20, and each R^(m) is anindependent hydrocarbon radical comprising 1-10 carbons. Accordingly, W′can be a divalent radical that includes those of Scheme 3.

In Scheme 3, each n is an independent integer having a value of 1 to 20,each R^(m) is an independent hydrocarbon radical comprising 1-10carbons, and the nitrogen or oxygen labeled 1 is linked to carbonylcarbon 1 of formula (1).

In an embodiment, L′ is

wherein d′ is an integer having a value of 1 to 6. In this instance, W′is

wherein d′ is an integer having a value of 1 to 6, and the starred bondof the methylene carbon is linked to the carbon 1 of formula (1).

In another embodiment, L′ is 1,2-ethylene and W′ is

wherein methylene carbon 1 is linked to carbonyl carbon 1 of formula(1).

L^(a) and L^(b) can be the same or different hydrocarbon groups.Exemplary non-limiting L^(a) and L^(b) groups include 1,1-ethylene,1,2-ethylene, 1,1-propylene, 1,3-propylene, 1,1-butylene, 1,4-butylene,and 1,1-pentylene, 1,5-pentylene, 1,2-cyclohexylene, 1,3-cyclohexylene,1,4-cyclohexylene, 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene.

In a preferred embodiment, each of L^(a) and L^(b) is independentlyselected from alkylene groups of formula (3):

wherein n′ is an integer having a value of 2 to 6. In anotherembodiment, L^(a) and L^(b) are 1,2-ethylene.

Exemplary non-limiting Q′ groups include structures of formulas (4)-(7):

wherein

R^(a), R^(b), R^(c), R^(d), R^(e) are independent monovalent hydrocarbongroups comprising 1-20 carbons, and

each X⁻ is an independent negative-charged counterion.

Exemplary R^(a), R^(b), R^(c), R^(d), R^(e) monovalent hydrocarbongroups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, cyclopentyl, n-hexyl,cyclohexyl, and benzyl.

Exemplary negative-charged X⁻ counterions include halides (e.g.,fluoride, chloride, bromide, iodide), hydroxide, alkoxides, aryloxides,alkyl and aryl carboxylates (e.g., acetate, benzoate), hydrogencarbonate, alkyl and aryl sulfonates (e.g., methanesulfonate,p-toluenesulfonate), methyl sulfate, hydrogen sulfate, nitrate,dihydrogen phosphate, dialkyl and diaryl phosphates, and alkyl and arylphosphonates.

The polyamine can comprise the cationic repeat units singularly or incombination.

More specific polyamines comprise a polymeric repeat unit of formula(8):

wherein

W″ is a single bond or a divalent linking group having a structure*—C(═O)-L″-*, wherein L″ is divalent radical comprising 1-20 carbons andL″ is linked to carbonyl carbon 1,

L^(c) and L^(b) are independent divalent linking groups selected fromthe group consisting of a single bond, and hydrocarbon groups comprising1-6 carbons, and

P′ is a divalent poly(alkylene oxide) chain.

L″ can be any of the above-described groups for L′, and W″ can be any ofthe above-described groups for W′, where it should be understood thatthe atomic centers linked to carbonyl carbon 1 of formula (1) for W′ arelinked to carbonyl carbon 1 of formula (8) for W″. In an embodiment, L″is the same as L′ and W″ is the same as W′.

L^(c) and L^(d) can be the same or different hydrocarbon groups.Exemplary non-limiting L and L^(d) groups include 1,1-ethylene,1,2-ethylene, 1,1-propylene, 1,2-propylene, 1,3-propylene, 1,1-butylene,1,2-butylene, 1,3-butylene, 1,4-butylene, 1,1-pentylene, 1,2-pentylene,1,3-pentylene, 1,4-pentylene, 1,5-pentylene, 1,2-cyclohexylene,1,3-cyclohexylene, 1,4-cyclohexylene, 1,2-phenylene, 1,3-phenylene, and1,4-phenylene. In an embodiment, L^(c) is 1,2-propylene, wherein P′ islinked to the 1 position of 1,2-propylene, and L^(d) is a single bond.In another embodiment, L is 1,2-ethylene and L^(d) is a single bond.

P′ is a hydrophilic poly(alkylene) oxide chain comprising ethylene oxideand/or propylene oxide repeat units. P′ can be a homopolymer of ethyleneoxide (referred to as a PEG chain), or of propylene oxide units(referred to as a PPO chain). P′ can be a random copolymer comprisingethylene oxide and propylene oxide repeat units. P′ can be a blockcopolymer comprising 2 or more blocks comprising ethylene oxide andpropylene oxide repeat units. For example, P′ can be a diblock copolymerchain comprising a PEG block and a PPO block (denoted as *-PEG-b-PPO-*),wherein each block has an average degree of polymerization (DP) greaterthan 1. Alternatively, P′ can be a triblock copolymer chain (e.g.,*-PPO-b-PEG-b-PPO-* or *-PEG-b-PPO-b-PEG-*). One or more of the blocksof the block copolymer can be a random copolymer chain comprisingethylene oxide and propylene oxide repeat units (e.g.,*-PPO-b-[PPO-r-PEO]-b-PEO-*, where the center block is a randomcopolymer chain).

A PEG chain has the structure:

where n has an average value greater than 1.

A PPO chain has the structure:

where n has an average value of greater than 1.

In an embodiment, P′ has a triblock structure according to formula (9):

wherein

r, s, and t represent degrees of polymerization of respective blocks ofalkylene oxide repeat units enclosed in the brackets,

r, s, and t independently have average values greater than 1.

In an embodiment, s/(r+t) has a value of about 2 to about 12.

P′ can have a number average molecular weight of about 500 to about5000. More specifically, P′ can have a number average molecular weightof about 1500 to about 2500.

More specific polymeric repeat units have a structure according toformula (10):

wherein

W″ is a single bond or a divalent linking group having a structure*—C(═O)-L″-*, wherein L″ is divalent radical comprising 1-20 carbons andL″ is linked to carbon 1,

r, s, and t represent average numbers of respective alkylene oxiderepeat units, and

r, s, and t independently have average values greater than 1.

The polyamine can comprise the polymeric repeat units singularly or incombination.

When present, the polymeric repeat unit is present in an amount of morethan 0 mol % to about 10 mol % based on total moles of repeat units ofthe polyamine, wherein molecular weight of P′ is based on number averagemolecular weight (Mn).

Preparation of Cationic Polyamides

The cationic polyamides are preferably prepared by a step-growthpolymerization performed in bulk using a base organocatalyst (e.g.,1,8-diazabicycloundec-7-ene (DBU), 1,5-diazabicyclo(4.3.0)non-5-ene(DBN), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)).

The reaction mixture contains a “carbonyl monomer”. The carbonyl monomercan comprise a carbonate compound capable of reacting with two primaryamine groups to form a urea. Exemplary non-limiting carbonyl monomers ofthis type include diethyl carbonate, diphenyl carbonate, andbis-pentafluorophenyl carbonate.

Other carbonyl monomers comprise two carbonyl groups in the form ofcarboxylic ester groups, carbonate groups, carbamate groups, or acombination thereof. In this instance, each of the two carbonyl groupsof the carbonyl monomer is capable of reacting with a primary amine toform an amide, carbamate, or a urea group.

The reaction mixture also contains an amine monomer comprising twoprimary amine groups and a tertiary amine group. The tertiary aminegroup is capable of forming positive charged quaternary ammonium groupin a reaction with an alkylating agent (quaternizing agent).

In a preferred embodiment, the reaction mixture also comprises a secondreactive diamine comprising a poly(alkylene oxide) chain terminated ateach end by a primary amine group. This reactant is referred to hereinas the “polyether diamine”.

The carbonyl monomer, the amine monomer, organocatalyst, and optionallythe polyether diamine can be heated together without solvent at atemperature of about 100° C. to 200° C. in one or more heating stages toeffect polymerization. The reaction time can vary from about 1 hour toabout 24 hours. Optionally, vacuum can be applied to remove alcoholbyproduct and assist in driving the reaction to completion. The bulkpolymerization generates an initial polymer that can precipitate duringthe reaction.

Exemplary non-limiting amine monomers include those of formula (11):

wherein

R^(a) is a monovalent hydrocarbon group comprising 1-20 carbons, and

j and j′ are independent integers having values of 0 to 18.

In an embodiment, R^(a) is methyl, j is 1, and j′ is 1 of formula (11).

Other amine monomers include those of formula (12):

wherein j and j′ are independent integers having values of 0 to 18.

In an embodiment, j is 1 and j′ is 1 of formula (12).

Other amine monomers include those of formula (13):

wherein k and k′ are independent integers having values of 1 to 20.

The amine monomers can be used singularly or in combination.

No restriction is placed on carbonyl monomers comprising two carbonylgroups, with the proviso that the desirable properties of the cationicpolyamine are not adversely affected (biodegradability, antimicrobialactivity, hemolysis, and cytotoxicity) by the structure of the carbonylmonomer. The carbonyl monomers can be used singularly or in combination.

Carbonyl monomers comprising two carbonyl groups include diestermonomers such as, for example, dimethyl malonate, diethyl malonate,diethyl 2-methylmalonate, diethyl 2-propylmalonate, diethyl2-iso-propylmalonate, diethyl 2-n-butylmalonate, dimethylisobutylmalonate, 2-tert-butylmalonate, diethyl 2-pentylmalonate,diethyl 2-heptylmalonate, diethyl 2-hexylmalonate, dimethyl succinate,diethyl succinate, dimethyl glutarate, diethyl glutarate, dimethyladipate, diethyl adipate, dimethyl pimelate, diethyl pimelate, diethyl1,1-cyclohexanedicarboxylate, diethyl 1,4-cyclohexanedicarboxylate,dimethyl terephalate, dimethyl isophthalate. The diester monomer cancomprise alkyl esters, aryl esters, and combinations thereof.

Exemplary non-limiting carbonyl monomers comprising two carbamate groupsinclude compounds of formula (13):

wherein

n is an integer having a value of 2-20, and

each R^(f) is selected from the group consisting of methyl, ethyl,t-butyl, and phenyl.

Each hydrogen of the methylene groups enclosed in parentheses of formula(13) can optionally be substituted with an alkyl or aryl substituent(e.g., methyl, ethyl, or phenyl).

Other non-limiting carbonyl monomers comprising two carbamate groupsinclude compounds of formula (14):

wherein

each R^(g) is selected from the group consisting of methyl, ethyl,t-butyl, and phenyl.

In an embodiment, each R of formula (14) is t-butyl.

Exemplary non-limiting carbonyl monomers comprising two carbonate groupsinclude ethylene glycol bis(2-chloro-4-nitrophenyl carbonate), propyleneglycol bis(2-chloro-4-nitrophenyl carbonate), butylene glycolbis(2-chloro-4-nitrophenyl carbonate), and 1,4-butylene glycolbis(2-chloro-4-nitrophenyl carbonate), diethylene glycolbis(2-chloro-4-nitrophenyl carbonate), dipropylene glycolbis(2-chloro-4-nitrophenyl carbonate), dibutylene glycolbis(2-chloro-4-nitrophenyl carbonate), triethylene glycolbis(2-chloro-4-nitrophenyl carbonate), tripropylene glycolbis(2-chloro-4-nitrophenyl carbonate), tributylene glycolbis(2-chloro-4-nitrophenyl carbonate), tetraethylene glycolbis(2-chloro-4-nitrophenyl carbonate, tetrabutylene glycolbis(2-chloro-4-nitrophenyl carbonate), pentapropylene glycol bis(2-chloro-4-nitrophenyl carbonate), and octaethylene glycolbis(2-chloro-4-nitrophenyl carbonate). The 2-chloro-4-nitrophenyl groupsof each of the foregoing compounds can be replaced with any suitableactivating group such as, for example, p-nitrophenyl, pentachlorophenyl,pentafluorophenyl, and the like.

The carbonyl monomers can be used singularly or in combination.

The polyether diamine has a structure in accordance with formula (15):H₂N-L^(c)-P′-L^(d)-NH₂  (15),wherein

L^(c) and L^(d) are independent divalent linking groups selected fromthe group consisting of a single bond, and hydrocarbon groups comprising1-6 carbons, and

P′ is a divalent poly(alkylene oxide) chain.

P′ can be a homopolymer, random copolymer, or block copolymer comprisingalkylene oxide repeat units. Especially preferred alkylene oxides unitsare ethylene oxide and propylene oxide.

Exemplary non-limiting polyether diamines include diamine terminatedtriblock copolymers poly(propylene oxide)-block-poly(ethyleneoxide)-block-poly(propylene oxide):

diamine terminated homopolymers of propylene oxide:

diamine terminated homopolymers of ethylene oxide:

anddiamine terminated random copolymers of ethylene oxide and propyleneoxide represented by formula (16):

wherein

n represents the average number of ethylene oxide repeat units,

m represents the average number of propylene oxide repeat units,

each of n and m has an average value greater than 1, and

R is H or methyl.

In the above notation, the stacking of repeat units within the squarebrackets represents a random distribution of the repeat units in thepolymer chain. The starred bonds of each repeat unit overlapping theleft bracket can be bonded to a different repeat unit at an attachmentpoint indicated by the starred bonds of the repeat units overlapping theright square bracket, or to the end group represented by the structureH₂N—C(R)CH₂—*. Likewise, the starred bonds of the repeat unitsoverlapping the right bracket can be bonded to a different repeat unitat an attachment point indicated by the starred bonds of the repeatunits overlapping the right square bracket, or to an end grouprepresented by *—NH₂. Subscripts n and m represent independent averagenumbers of respective repeat units enclosed in the parentheses. Thepolyether diamines can be used singularly or in combination.

A polyether diamine can have a number average molecular weight (Mn) ofabout 500 to about 5000. A polyether diamine can have a weight averagemolecular weight (Mw) of about 1000 to about 25000.

Quaternization

The initial polymer formed is treated with a suitable nitrogenquaternizing agent to convert the tertiary amine groups of the initialpolymer to positive charged quaternary ammonium groups. The quaternizingagent can be any suitable material. such as, for example, an alkylhalide, alkyl sulfonate, and/or benzyl halide. The quaternizing agentscan be used singularly or in combination. In an embodiment, thequaternizing agent is methyl iodide and/or benzyl bromide.

Molecular Weight

The polyamines can have a number average molecular weight (Mn) of about700 to about 25000. The polyamines can have a weight average molecularweight (Mw) of about 1000 to about 50000.

Antimicrobial Properties

For the examples further below, the following definitions areapplicable.

HC50 is defined as the concentration (in mg/L) of cationic polyaminethat causes 50% of mammalian red blood cells to undergo hemolysis. HC50values of 1000 mg/L or higher are desirable.

HC20 is defined as the concentration (in mg/L) of cationic polyaminethat causes 20% of mammalian red blood cells to undergo hemolysis. HC20values of 500 mg/L or higher are desirable.

Minimum inhibitory concentration (MIC) is defined as the minimumconcentration (in mg/L) of cationic polyamine required to inhibit growthof a given microbe for an 18 hour period (bacteria) or 42 hour period(fungi). A MIC less than 500 mg/L is desirable. Even more desirable is aMIC of 150 mg/L or less. A lower MIC indicates higher antimicrobialactivity.

Minimum bactericidal concentration (MBC) is defined as the minimumconcentration (in mg/L) of cationic polyamine required to kill a givenmicrobe. A lower MBC indicates higher antimicrobial activity.

HC50 selectivity is defined as the ratio of HC50/MIC. An HC50selectivity of 3 or more is desirable. Higher HC50 selectivity valuesindicate more activity against bacterial cells and less toxicity tomammalian cells. Likewise, HC20 selectivity is defined as the ratio ofHC20/MIC. An HC20 selectivity of 3 or more is desirable.

Non-limiting exemplary bacteria include Gram-positive Staphylococcusaureus (S. aureus), Gram-negative Escherichia coli (E. coli), fungusCandida albicans (C. albicans), Gram-negative Pseudomonas aeruginosa (P.aeruginosa), and yeasts. Other microbes include Gram-positiveStaphylococcus epidermidis (S. epidermidis), Gram-positiveMethicillin-resistant Staphylococcus aureus (MRSA), Gram-positiveVancomycin-resistant Enterococcus (VRE), Gram-negative Acinetobacterbaumannii (A. baumannii), and Gram-negative Klebsiella pneumoniae (K.pneumoniae) and Cryptococcus neoformans (C. neoformans).

The polyamines can have a minimum inhibitory concentration (MIC) ofabout 8 mg/L to about 500 mg/L, and more preferably about 8 mg/L toabout 250 mg/L, and most preferably 8 mg/L to about 125 mg/L against abacterium. In an embodiment, the cationic polyamines can have a MIC ofabout 8 mg/L to about 63 mg/L against P. aeruginosa.

The cationic polyamines can exhibit less than about 50% hemolysis at1000 mg/L (i.e., can have an HC50 value greater than 1000 mg/L).

The repeat unit comprising the poly(alkaline oxide) chain, when present,can substantially improve skin cell viability at concentrations higherthan MIC without adversely affecting microbial toxicity.

INDUSTRIAL APPLICABILITY

The cationic polyamines have utility as antimicrobial components ofconsumer products that are used in contact with skin such as, forexample, cosmetics (e.g., skin lotions, skin creams, topically appliedpowders, mascara, eye liners, lip glosses), soaps, shampoos, anddeodorants. The cationic polyamines also have utility as antimicrobialcomponents of laundry detergents.

The cationic polyamines also have utility for human and/or non-humantherapeutic medical treatments. The polyamines can be used in the formof a stand-alone antibiotic drug and/or as a complex comprising thepolyamine and an anionic form of biologically active material (e.g.,genes, drugs) bound by non-covalent interactions. A medical compositioncomprising the polyamine and/or a biologically active material selectedfrom the group consisting of genes, drugs, and combinations thereof, canbe administered topically, intravenously, orally, by way of other bodycavities, and/or by inhalant. The medical composition can have the formof a powder, a pill, a liquid, a paste, or a gel. The medicalcompositions are particularly attractive for use in injectable systemsfor delivery of rigid, hydrophobic biologically active materials thathave low water solubility, such as the drugs paclitaxel and doxorubicin.

A method comprises contacting a microbe with a polyamine, therebykilling the microbe.

Another method comprises contacting a tumor cell with a complexcomprising a disclosed polyamine and a tumor-treating drug, therebykilling the tumor cell.

An antimicrobial composition comprises a disclosed polyamine and atleast one other component (e.g., water, drug, gene). The antimicrobialcomposition can be applied to a human and/or non-human animal tissue,including mammalian and/or non-mammalian animal tissue. The general term“animal tissue” includes wound tissue, burn tissue, skin, internal organtissue, blood, bones, cartilage, teeth, hair, eyes, nasal surfaces, oralsurfaces, other body cavity surfaces, and any cell membrane surfaces. Inan embodiment, a method comprises contacting an animal tissue with theantimicrobial composition, thereby inhibiting, preventing, and/oreradicating a microbial infection of the tissue.

Other uses of the polyamines include disinfectant washes for hands,skin, hair, bone, ear, eye, nose, throat, internal tissue, wounds, andteeth (e.g., as a mouthwash).

Still other uses of the polyamines include disinfectants for articlessuch as medical devices. Medical devices include swabs, catheters,sutures, stents, bedpans, gloves, facial masks, absorbent pads,absorbent garments, internal absorbent devices, and insertablemechanical devices. In an embodiment, a method comprises contacting amedical device with an antimicrobial composition comprising a disclosedpolyamine, thereby disinfecting the medical device. In an embodiment,the medical device is a catheter.

The antimicrobial compositions are also attractive as disinfectingagents for surfaces of articles (i.e., non-living articles) such as, forexample, building surfaces in homes, businesses, and particularlyhospitals. Exemplary home and commercial building surfaces includefloors, door surfaces, bed surfaces, air conditioning surfaces, bathroomsurfaces, railing surfaces, kitchen surfaces, and wall surfaces. Otherarticles include medical devices, cloths, garments, and non-medicalequipment. Surfaces of articles can comprise materials such as wood,paper, metal, cloth, plastic, rubber, glass, paint, leather, orcombinations thereof. In an embodiment, a method comprises contacting asurface of an article with an antimicrobial composition comprising adisclosed polyamine, thereby disinfecting the surface. In anotherembodiment, the antimicrobial composition has the form of a solution.

In an embodiment, the antimicrobial composition is selected from thegroup consisting of soaps, shampoos, skin lotions, skin creams,cosmetics, mouthwashes, wound care agents, deodorants, surface cleaningagents, and laundry detergents.

Polyamine Complexes

In water, optionally containing organic solvent, the polyamines can forma nanoparticulate complex with an anionic biologically active cargomaterial, bound by non-covalent interactions. These “loaded” complexescan have the form of a micelle that comprises a plurality ofself-assembled macromolecules of the polyamine and one or more moleculesof the cargo material encapsulated therein.

A method of forming a nanoparticulate polyamine complex comprises i)forming a first solution comprising a polyamine (i.e., carrier) andwater; ii) forming a second solution comprising a biologically activematerial (i.e., cargo) in water and/or a water miscible organic solvent;iii) combining the first and seconds solutions; and iv) removing anyorganic solvent (e.g., by dialysis), thereby forming an aqueous mixturecomprising the complex. The complex can comprise the polyamine in anamount of 85.0 wt. % to 99.9 wt. %, and the biologically active materialin an amount of about 15.0 wt. % to 0.1 wt. %, each based on total drysolids weight of the complex.

The term “loading efficiency” refers to the percentage of the initialweight of the biologically active material that is incorporated into thepolyamine complex. The loading efficiency of the biologically activematerial in the polyamine complex is preferably at least 10%. Generally,the loading efficiency of the biologically active material is in a rangeof 10% to 50%, and even more specifically in a range of 30% to 50%.

Nanoparticles of the polyamine complex can have an average particle size(circular cross sectional diameter) of 10 nm to 500 nm, 10 nm to 250 nm,and preferably 25 nm to 200 nm as measured by dynamic light scattering.For the foregoing particle sizes, the aqueous solution can have a pH of4.5 to 8.0, 5.0 to 7.0, or 6.0 to 7.0.

The organic solvent, if any, used to prepare the polyamine complex ispreferably miscible with water at concentrations of at least 1microliter or more of organic solvent per 100 microliters of water.Exemplary organic solvents include methanol, ethanol, propanol,2-propanol, 1-butanol, 2-butanol, t-butyl alcohol, acetone, 2-butanone,dimethoxyethane, diglyme, diethyl ether, methyl t-butyl ether, methylenechloride, ethyl acetate, ethylene glycol, glycerin, dimethylsulfoxide,dimethylformamide, acetic acid, tetrahydrofuran (THF), and dioxane.

As stated above, the biologically active cargo material can be a drug.Exemplary commercially available drugs include the following, where thegeneric drug is enclosed in parentheses: 13-cis-Retinoic Acid, 2-CdA(Cladribine), 2-Chlorodeoxyadenosine (Cladribine), 5-Azacitidine,5-Fluorouracil (Fluorouracil), 5-FU (Fluorouracil), 6-Mercaptopurine,6-MP (6-Mercaptopurine), 6-TG (Thioguanine), 6-Thioguanine(Thioguanine), ABRAXANE® (Paclitaxel protein bound), ACCUTANE®(Isotretinoin), Actinomycin-D (Dactinomycin), ADRIAMYCIN® (Doxorubicin),ADRUCIL® (Fluorouracil), AFINITOR® (Everolimus), AGRYLIN® (Anagrelide),ALA-CORT® (Hydrocortisone), Aldesleukin, Alemtuzumab, ALIMTA®(Pemetrexed), Alitretinoin (9-cis-retinoic acid), Alkaban-AQ(Vinblastine), ALKERAN® (Melphalan), All-transretinoic Acid (Tretinoin),Alpha Interferon (Interferon Alfa), Altretamine, Amethopterin(Methotrexate), Amifostine, Aminoglutethimide, Anagrelide, ANANDRON®(Nilutamide), Anastrozole, Arabinosylcytosine (Cytarabine),Ara-C(Cytarabine), ARANESP® (Darbepoetin Alfa), AREDIA® (Pamidronate),ARIMIDEX® (Anastrozole), AROMASIN® (Exemestane), ARRANON® (Nelarabine),Arsenic Trioxide, Asparaginase, ATRA (All-transretinoic Acid), AVASTIN®(Bevacizumab), Azacitidine, BCG, BCNU (Carmustine), Bendamustine(Bendamustine Hydrochloride), Bevacizumab, Bexarotene, BEXXAR®(Tositumomab), Bicalutamide, BICNU® (Carmustine), BLENOXANE®(Bleomycin), Bleomycin, Bortezomib, Busulfan, BUSULFEX® (Busulfan), C225(Cetuximab), Calcium Leucovorin (Leucovorin), CAMPATH® (Alemtuzumab),CAMPTOSAR® (Irinotecan), Camptothecin-11 (Irinotecan), Capecitabine,CARAC® (Fluorouracil), Carboplatin, Carmustine, Carmustine Wafer,CASODEX® (Bicalutamide), CC-5013 (Lenalidomide), CCI-779 (Temsirolimus),CCNU (Lomustine), CDDP (Cisplatin), CEENU® (Lomustine), CERUBIDINE®(Daunomycin), Cetuximab, Chlorambucil, Cisplatin, Citrovorum Factor(Leucovorin), Cladribine, Cortisone (Hydrocortisone), COSMOGEN®(Dactinomycin), CPT-11 (Irinotecan), Cyclophosphamide, CYTADREN®(Aminoglutethimide), Cytarabine, Cytarabine Liposomal, CYTOSAR-U®(Cytarabine), CYTOXAN® (Cyclophosphamide), Dacarbazine, DACOGEN®(Decitabine), Dactinomycin, Darbepoetin Alfa, Dasatinib, Daunomycin,Daunorubicin, Daunorubicin Hydrochloride, Daunorubicin Liposomal,DAUNOXOME® (Daunorubicin Liposomal), DECADRON™ (Dexamethasone),Decitabine, DELTA-CORTEF® (Prednisolone), DELTASONE® (Prednisone),Denileukin Diftitox, DEPOCYT® (Cytarabine Liposomal), Dexamethasone,Dexamethasone Acetate, Dexamethasone Sodium Phosphate, DEXASONE®(Dexamethasone), Dexrazoxane, DHAD (Mitoxantrone), DIC (Dacarbazine),DIODEX® (Dexamethasone), Docetaxel, DOXIL® (Doxorubicin Liposomal),Doxorubicin, Doxorubicin Liposomal, DROXIA® (Hydroxyurea), DTIC(Dacarbazine), DTIC-DOME® (Decarbazine), Duralone (Methylprednisolone),EFUDEX® (Fluorouracil), ELIGARD® (Leuprolide), ELLENCE® (Epirubicin),ELOXATIN® (Oxaliplatin), ELSPAR® (Asparaginase), EMCYT® (Estramustine),Epirubicin, Epoetin Alfa, ERBITUX® (Cetuximab), Erlotinib, ErwiniaL-asparaginase (Asparaginase), Estramustine, ETHYOL® (Amifostine),ETOPOPHOS® (Etoposide), Etoposide, Etoposide Phosphate, EULEXIN®(Flutamide), Everolimus, EVISTA® (Raloxifene), Exemestane, FARESTON®(Toremifene), FASLODEX® (Fulvestrant), FEMARA® (Letrozole), Filgrastim,Floxuridine, FLUDARA® (Fludarabine), Fludarabine, FLUOROPLE®(Fluorouracil), Fluorouracil, Fluorouracil (cream), Fluoxymesterone,Flutamide, Folinic Acid (Leucovorin), FUDR® (Floxuridine), Fulvestrant,G-CSF (Pegfilgrastim), Gefitinib, Gemcitabine, Gemtuzumab ozogamicin,GEMZAR® (Gemcitabine), GLEEVEC® (Imatinib mesylate), GLIADEL® Wafer(Carmustine Wafer), GM-CSF (Sargramostim), Goserelin, Granulocyte—ColonyStimulating Factor (Pegfilgrastim), Granulocyte Macrophage ColonyStimulating Factor (Sargramostim), HALOTESTIN® (Fluoxymesterone),HERCEPTIN® (Trastuzumab), HEXADROL® (Dexamethasone), HEXALEN®(Altretamine), Hexamethylmelamine (Altretamine), HMM (Altretamine),HYCAMTIN® (Topotecan), HYDREA® (Hydroxyurea), Hydrocort Acetate(Hydrocortisone), Hydrocortisone, Hydrocortisone Sodium Phosphate,Hydrocortisone Sodium Succinate, HYDROCORTONE® Phosphate(Hydrocortisone), Hydroxyurea, Ibritumomab, Ibritumomab Tiuxetan(Ibritumomab), IDAMYCIN® (Idarubicin), Idarubicin, IFEX® (Ifosfamide),IFN-alpha (Interferon alfa), Ifosfamide, IL-11 (Oprelvekin), IL-2(Aldesleukin), Imatinib mesylate, Imidazole Carboxamide (Decarbazine),Interferon alfa, Interferon Alfa-2b (PEG Conjugate), Interleukin-2(Aldesleukin), Interleukin-11 (Oprelvekin), INTRON® A (interferonalfa-2b), IRESSA® (Gefitinib), Irinotecan, Isotretinoin, Ixabepilone,IXEMPRA® (Ixabepilone), Kidrolase (Asparaginase), LANACORT®(Hydrocortisone), Lapatinib, L-asparaginase, LCR (Vincristine),Lenalidomide, Letrozole, Leucovorin, LEUKERAN® (Chlorambucil), LEUKINE®(Sargramostim), Leuprolide, Leurocristine (Vincristine), LEUSTATIN®(Cladribine), Liposomal Ara-C, LIQUID PRED® (Prednisone), Lomustine,L-PAM (Melphalen), L-Sarcolysin (Melphalen), LUPRON® (Leuprolide),LUPRON DEPOT® (Leuprolide), MATULANE® (Procarbazine), MAXIDEX®(Dexamethasone), Mechlorethamine, Mechlorethamine Hydrochloride,Medralone (Methylpredni solone), MEDROL® (Methylprednisolone), MEGACE®(Megestrol), Megestrol, Megestrol Acetate (Megastrol), Melphalan,Mercaptopurine (6-Mercaptopurine), Mesna, MESNEX® (Mesna), Methotrexate,Methotrexate Sodium (Methotrexate), Methylprednisolone, METICORTEN®(Prednisone), Mitomycin (Mitomycin C), Mitomycin-C, Mitoxantrone,M-Prednisol (Methylprednisolone), MTC (Mitomycin-C), MTX (Methotrexate),MUSTARGEN® (Mechlorethamine), Mustine (Mechlorethamine), MUTAMYCIN®(Mitomycin-C), MYLERAN® (Busulfan), MYLOCEL® (Hydroxyurea), MYLOTARG®(Gemtuzumab ozogamicin), NAVELBINE® (Vinorelbine), Nelarabine, NEOSAR®(Cyclophosphamide), NEULASTA® (Pegfilgrastim), NEUMEGA® (Oprelvekin),NEUPOGEN® (Filgrastim), NEXAVAR® (Sorafenib), NILANDRON® (Nilutamide),Nilutamide, NIPENT® (Pentostatin), Nitrogen Mustard (Mechlorethamine),NOLVADEX® (Tamoxifen), NOVANTRONE® (Mitoxantrone), Octreotide,Octreotide acetate (Octreotide), ONCASPAR® (Pegaspargase), ONCOVIN®(Vincristine), ONTAK® (Denileukin Diftitox), ONXOL® (Paclitaxel),Oprelvekin (Interleukin-11), ORAPRED® (Prednisolone), ORASONE®(Prednisone), Oxaliplatin, Paclitaxel, Paclitaxel Protein-bound,Pamidronate, Panitumumab, PANRETIN® (Alitretinoin), PARAPLATIN®(Carboplatin), PEDIAPRED® (Prednisolone), PEG Interferon, Pegaspargase,Pegfilgrastim, PEG-INTRON® (Interferon Alfa-2b), PEG-L-asparaginase,Pemetrexed, Pentostatin, Phenylalanine Mustard (Melphalen), PLATINOL®(Cisplatin), Platinol-AQ (Cisplatin), Prednisolone, Prednisone, PRELONE®(Prednisolone), Procarbazine, PROCRIT® (Epoetin Alfa), PROLEUKIN®(Aldesleukin), Prolifeprospan 20 with Carmustine Implant (CarmustineWafer), PURINETHOL® (6-Mercaptopurine), Raloxifene, REVLIMID®(Lenalidomide), RHEUMATREX® (Methotrexate), RITUXAN® (Rituximab),Rituximab, Roferon-A (Interferon Alfa-2a), RUBEX® (Doxorubicin),Rubidomycin hydrochloride (Daunomycin), SANDOSTATIN® (Octreotide),SANDOSTATIN LAR® (Octreotide), Sargramostim, SOLU-CORTEF®(Hydrocortisone), SOLU-MEDROL® (Methylprednisolone), Sorafenib, SPRYCEL®(Dasatinib), STI-571 (Imatinib Mesylate), Streptozocin, SU11248(Sunitinib), Sunitinib, SUTENT® (Sunitinib), Tamoxifen, TARCEVA®(Erlotinib), TARGRETIN® (Bexarotene), TAXOL® (Paclitaxel), TAXOTERE®(Docetaxel), TEMODAR® (Temozolomide), Temozolomide, Temsirolimus,Teniposide, TESPA (Thiotepa), Thalidomide, THALOMID® (Thalidomide),THERACYS® (BCG), Thioguanine, Thioguanine Tabloid (Thioguanine),Thiophosphoamide (Thiotepa), THIOPLEX® (Thiotepa), Thiotepa, TICE®(BCG), TOPOSAR® (Etoposide), Topotecan, Toremifene, TORISEL®(Temsirolimus), Tositumomab, Trastuzumab, TREANDA® (BendamustineHydrochloride), Tretinoin, TREXALL® (Methotrexate), TRISENOX® (ArsenicTrioxide), TSPA (Thiotepa), TYKERB® (Lapatinib), VCR (Vincristine),VECTIBIX® (Panitumumab), VELBAN® (Vinblastine), VELCADE® (Bortezomib),VEPESID® (Etoposide), VESANOID® (Tretinoin), VIADUR® (Leuprolide),VIDAZA® (Azacitidine), Vinblastine, Vinblastine Sulfate, VINCASAR PFS®(Vincristine), Vincristine, Vinorelbine, Vinorelbine tartrate(Vinorelbine), VLB (Vinblastine), VM-26 (Teniposide), Vorinostat, VP-16(Etoposide), VUMON® (Teniposide), XELODA® (Capecitabine), ZANOSAR®(Streptozocin), ZEVALIN® (Ibritumomab), ZINECARD® (Dexrazoxane),ZOLADEX® (Goserelin), Zoledronic acid, ZOLINZA® (Vorinostat), andZOMETA® (Zoledronic acid).

The following examples demonstrate the preparation, antimicrobialproperties, hemolytic properties, and cytotoxicity of the polyamines.

EXAMPLES

Materials used in the following examples are listed in Table 1.

TABLE 1 ABBRE- VIATION DESCRIPTION SUPPLIER BAPPIP 1,4-Bis(3-Sigma-Aldrich aminopropyl)piperazine BnBr Benzyl bromide Sigma-AldrichDAMDPA 3,3′- diamino-N- Sigma-Aldrich methyldipropylamine DBocGDi-boc-guanidine Sigma-Aldrich DEC Diethyl carbonate Sigma-AldrichDESucc Diethyl succinate Sigma-Aldrich DMEM Dulbecco's ModifiedInvitrogen Eagle Medium DMM Dimethyl 2-methylmalonate Sigma-Aldrich DMSDimethyl sulfate Sigma-Aldrich ED-2003 Triblock copolymer O,O′-Sigma-Aldrich Bis(2-aminopropyl) polypropylene glycol-block-polyethyleneglycol-block-polypropylene glycol; JEFFAMINE; Mn 1900 FBS Fetal BovineSerum Invitrogen HDF Human dermal fibroblasts ATCC, USA HexBr n-Hexylbromide Sigma-Aldrich MDEA N-methyldiethanolamine Sigma-Aldrich MHBMueller Hinton Broth BD Diagnostics, SG MTT3-[4,5-Dimenthylthiazol-2-yl]- Invitrogen 2,5-diphenyl tetrazoliumbromide PBS Phosphate Buffered Saline 1^(st) Base, SG TBD1,5,7-Triazabicyclo[4.4.0]dec- Sigma-Aldrich 5-ene TSB Tryptic Soy BrothBD Diagnostics, SG YMB Yeast Mold Broth BD Diagnostics, SG

Herein, Mn is the number average molecular weight, Mw is the weightaverage molecular weight, and MW is the molecular weight of onemolecule.

¹H NMR spectra were acquired on a Bruker Avance 400 instrument at 400MHz. Gel permeation chromatography (GPC) was performed intetrahydrofuran (THF) using a Waters system equipped with four5-micrometer Waters columns (300 mm×7.7 mm) connected in series withincreasing pore size (100, 1000, 105, and 106 angstroms), a Waters 410differential refractometer, and a 996 photodiode array detector. Thesystem was calibrated using polystyrene standards. GPC analysis was alsoperformed in N,N-dimethylformamide (DMF) spiked with 0.01 M LiBr using aWaters system equipped with two Agilent PolyPore columns (300 mm×7.5 mm)connected in series, a Waters 410 differential refractometer. The systemwas calibrated with poly(methyl methacrylate) standards. GPC analysiswas also performed in 54/23/23 (v/v/v %) water/methanol/acetic acid(H₂O/MeOH/AcOH) with 0.5 M sodium acetate (NaOAc) using a Waters systemequipped with two Agilent PolyPore columns (300 mm×7.5 mm) connected inseries, a Waters 410 differential refractometer. The system wascalibrated with poly(ethylene oxide) standards.

All chemical reagents were purchased from Sigma-Aldrich, U.S.A. and usedas received unless otherwise specified. Tryptic Soy Broth (TSB), YeastMold Broth (YMB) and Muller Hinton Broth (MHB) powder were purchasedfrom BD Diagnostics (Singapore) and used to prepare the microbial brothsaccording to the manufacturer's instruction. Cell lines of human dermalfibroblasts (HDF), Staphylococcus aureus (ATCC No. 6538, S. aureus),Escherichia coli (ATCC No. 25922, E. coli), Pseudomonas aeruginosa (ATCCNo. 9027, P. aeruginosa), and Candida albicans (ATCC No 10231, C.albicans) were obtained from ATCC, U.S.A., and reconstituted accordingto the suggested protocols. Fetal bovine serum (FBS) was purchased fromInvitrogen Corporation. 3-[4,5-Dimenthylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) was dissolved in phosphate-buffered saline(PBS, pH 7.4) with a concentration of 5 mg/mL, and the solution wasfiltered with a 0.22 micron filter to remove blue formazan crystalsprior to usage. Rat red blood cells (RBCs) were obtained from the AnimalHandling Unit of Biomedical Research Centers (Singapore).

Synthesis

The P31 series of polymers, P31a-d, was prepared according to thefollowing reaction diagram, where n represents the average number ofrepeat units enclosed in the parentheses.

Example 1

Preparation of polymer P31a. N-methyldiethanolamine (MDEA, 0.68 g,0.0057 mol), dimethyl 2-methylmalonate (DMM, 0.99 g, 0.0057 mol) and TBD(0.05 g, 0.00035 mol) were charged in a Schlenk tube. The reactants weremixed by simple vortex until miscible (1-2 minutes). The Schlenk tubewas placed in a heated sand bath at 80° C. After about 4 hours, vacuumwas applied to pull off the bi-product and shift the equilibrium towardsproduct. The reaction was allowed to continue for another 20 hours. Theintermediate polymer I1 crystallized, limiting the molecular weight. Mn(GPC, DMF=14000 g/mol, PDI=1.23, n=69 based on Mn). In the abovestructure of I1, E′ and E″ are end groups.

Potential E′ groups of polymer I1 include MeO—* and

Potential E″ groups of polymer I1 include: *—H and

Intermediate polymer I1 was dissolved in DMF (up to 100° C.), and oncedissolved was separated into 4 vials (˜0.5 g in DMF (8-10 ml)). One ofsamples was quaternized (50° C., 24 hours) with methyl iodide (0.5 g,1.5 eq. (equivalents)). The polymer P31a was isolated by precipitationin diethyl ether. The polymer P31a was rinsed 3 times with diethyl etherand further purified via dialysis.

Example 2

P31b was prepared by charging one of the sample vials containing polymerI1 with dimethyl sulfate (DMS, 0.5 g, 1.5 eq.) following the generalprocedure above for P31a.

Example 3

P3c was prepared by prepared by charging one of the sample vialscontaining polymer I1 with benzyl bromide (BnBr, 0.6 g, 1.5 eq.)following the general procedure above for P31a.

Example 4

P3 d was prepared by prepared by charging one of the sample vialscontaining polymer I1 with hexyl bromide (HexBr, 0.6 g, 1.5 eq.)following the general procedure above for P31a.

In the above structures of P31a-d, Z′ and Z″ are end groups. PotentialZ′ groups of the P31a-d polymers include MeO—* and

Potential Z″ groups of the P31a-d polymers include *—H, the R group ofRX, and

Polymers P32a-d were prepared according to the following reactiondiagram, where n and represents the average number of repeat unitsenclosed in the parentheses, and n=95.

Example 5

Preparation of P32a. 3,3′-Diamino-N-methyldipropylamine (DAMDPA, 0.98 g,0.0066 mol), DMM (1.14 g, 0.0066 mol) and TBD (0.05 g, 0.00035 mol) werecharged in a Schlenk tube. The reactants were mixed by simple vortexuntil miscible (1-2 min). The Schlenk tube was placed in a heated sandbath at 80° C. After about 4 hours, vacuum was applied to remove themethanol byproduct and shift the equilibrium towards product. Thereaction was allowed to continue for another 20 hours. The intermediatepolymer I5 crystallized, thereby limiting the molecular weight. Mn (GPC,DMF=21600 g/mol, PDI=1.43, n=95 based on Mn).

Potential E′ end groups of I5 include MeO—* and

Potential E″ end groups of I5 include *—H and

Intermediate polymer I5 was dissolved in DMF (up to 100° C.), and oncedissolved was separated into vials (˜0.5 g in DMF (8-10 ml)). One of thesamples was quaternized (90° C., 24 hours) with methyl iodide (0.5 g,1.5 eq.), forming P32a. The polymer P32a was isolated by precipitationin diethyl ether. The polymer P32a (n=95) was rinsed 3 times withdiethyl ether and further purified via dialysis.

Example 6

P32b (n=95) was prepared by charging one of the sample vials containingpolymer I5 with dimethyl sulfate (DMS, 0.5 g, 1.5 eq.) following thegeneral procedure above for P32a.

Example 7

P32c (n=95) was prepared by prepared by charging one of the sample vialscontaining polymer I5 with benzyl bromide (BnBr, 0.6 g, 1.5 eq.)following the general procedure above for P32a.

Example 8

P32d (n=95) was prepared by prepared by charging one of the sample vialscontaining polymer I5 with hexyl bromide (HexBr, 0.6 g, 1.5 eq.)following the general procedure above for P32a.

Potential Z′ end groups of the P32a-d polymers include MeO—*,

and the like.

Potential Z″ end groups of the P32a-d polymers include *—H, the R groupof RX,

and the like.

Polymers P34a-c were prepared according to the following reactiondiagram, where n represents the average number of repeat units enclosedin the parentheses, and n=74.

Example 9

Preparation of P34a. 1,4-Bis(3-aminopropyl)piperazine (BAPPIP, 1.57 g,0.0078 mol), DMM (1.36 g, 0.0078 mol) and TBD (0.05 g, 0.00035 mol) werecharged in a Schlenk tube. The reactants were mixed by simple vortexuntil miscible (1-2 minutes). The reaction was allowed to react at roomtemperature for 4 hours and then the Schlenk tube was placed in a heatedsand bath (80° C., 10 hours). Vacuum was applied to drive off thebi-product and shift the equilibrium towards product. The intermediatepolymer I9 crystallized, limiting the molecular weight. Mn (GPC,DMF=20900 g/mol, PDI=1.55, n=74 based on Mn).

Potential E′ end groups of I9 include MeO—* and

Potential E″ end groups of I9 include *—H and

Intermediate polymer I9 was dissolved in DMF (up to 100° C.), and oncedissolved was separated into vials (˜0.5 g in DMF (8-10 ml)). One of thesamples was quaternized (80° C., 24 hours) with methyl iodide (0.5 g,1.5 eq.), forming P34a. The polymer P34a was isolated by precipitationin diethyl ether. The polymer P34a (n=74) was rinsed 3 times withdiethyl ether and further purified via dialysis.

Example 10

P34b (n=74) was prepared by charging one of the sample vials containingpolymer I9 with dimethyl sulfate (0.5 g, 1.5 eq.) following the generalprocedure above for P34a.

Example 11

P34c (n=74) was prepared by prepared by charging one of the sample vialscontaining polymer I9 with benzyl bromide (0.6 g, 1.5 eq.) following thegeneral procedure above for P34a.

Potential Z′ end groups of polymers P34a-c include MeO—*,

and the like.

Potential Z″ end groups of polymers P34a-c include *—H, the R group ofRX,

and the like.

Example 12

Preparation of P38 (n=20, RX=methyl iodide).

Diphenylcarbonate (DPC, 1.89 g, 0.0088 mol), N-methyldiethanolamine(MDEA, 1.05 g, 0.0088 mol) and TBD (0.05 g, 0.00035 mol) were charged ina Schlenk tube. The reactants were mixed by simple vortex until miscible(1-2 minutes). The Schlenk tube was placed in a heated sand bath (90°C.) and vacuum was applied to pull off the bi-product and shift theequilibrium towards product. The reaction was allowed to continue for 20hours. The polymerization evolved phenol that eventually sublimed andclogged the valve to the vacuum. The intermediate polymer I12 wasdissolved and isolated by filtration to remove the phenol bi-product. Mn(GPC, DMF=3000 g/mol, PDI=1.50, n=20 based on Mn).

Potential E′ groups of I12 include PhO—* and

Potential E″ groups of I12 include: *—H and

Intermediate polymer I12 was dissolved in DMF and was quaternized (50°C., 24 hours) with methyl iodide. The polymer P38 was rinsed 3 timeswith diethyl ether and further purified via dialysis.

Potential Z′ groups of polymer P38 include PhO—* and

Potential Z″ groups of polymer P38 include *—H, methyl and

Polymers P48a-b and polymers P49a-b were prepared according to thefollowing reaction diagram, where subscripts u and v represent mol % ofthe repeating unit enclosed in parentheses, and subscripts r, s, and t,represent average number of repeating units in the brackets. Thevertical stacking of the repeat units within the square bracketsindicates a random distribution of the repeat units.

Example 13

Preparation of P48a (u=100 mole %, v=0 mole %, no ED-2003). Diethylsuccinate (DESucc, 1.15 g, 0.0063 mol),3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.92 g, 0.0063 mol) and TBD(0.05 g, 0.00035 mol) were charged in a Schlenk tube. The reactants weremixed by simple vortex until miscible (1-2 minutes). The reaction wasallowed to react at room temperature for 4 hours and then the Schlenktube was placed in a heated sand bath (80° C., 10 hours). Vacuum wasapplied to drive off the bi-product and shift the equilibrium towardsproduct. The polymer I13 crystallized, limiting the molecular weight.

Potential E′ end groups of intermediate polymer I13 include EtO—* and

Potential E″ end groups of intermediate polymer I13 include *—H and

Intermediate polymer I13 was marginally soluble in DMF after heating to120° C. Once dissolved and homogenous, polymer I13 was quaternized (85°C., 24 hours) with benzyl bromide (2 g, 1.5 eq.). The polymer P48a(u=100 mole %, v=0 mole %) was isolated by precipitation in THF. Thepolymer was rinsed 3 times with diethyl ether and further purified viadialysis. Mn (aqueous GPC)=4,510 g/mol, PDI=2.19. FIG. 1 is a ¹H NMRspectrum of P48a.

Potential Z′ end groups of P48a include EtO—*,

and the like.

Potential Z″ end groups of P48a include *—H, benzyl,

and the like.

Example 14

Preparation of P48b (u=95 mole %, v=5 mole %) using 5 mol % ED-2003.Diethyl succinate (DESucc, 1.02 g, 0.0058 mol),3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.83 g, 0.0055 mol), ED-2003(0.58 g, 0.00029 mol, s˜39, r+t˜6) and TBD (0.05 g, 0.00035 mol) werecharged in a Schlenk tube. The reactants were mixed by simple vortexuntil miscible (1-2 minutes). The reaction was allowed to react at roomtemperature for 4 hours and then the Schlenk tube was placed in a heatedsand bath (80° C., 10 hours). Vacuum was applied to drive off thebi-product and shift the equilibrium towards product. The polymer I14crystallized, limiting the molecular weight.

Potential E′ end groups of intermediate polymer I14 include thosementioned above for polymer I13, and

Potential E″ end groups of intermediate polymer I14 include thosementioned above for polymer I13.

Intermediate polymer I14 was marginally soluble in DMF after heating to120° C. for 2-3 hours. Once dissolved and homogenous, the polymer wasquaternized (85° C., 24 hours) with benzyl bromide (2.8 g, 1.5 eq.). Thepolymer P48b was isolated by precipitation in THF. The polymer P48b(u=95 mole %, v=5 mole %) was rinsed 3 times with diethyl ether andfurther purified via dialysis. Mn (Aqueous GPC)=1,960 g/mol, PDI=1.66.FIG. 2 is a ¹H NMR spectrum of P48b.

Potential Z′ end groups of the P48b polymer include those mentionedabove for P48a, and also

Potential Z″ end groups of polymer P48b include those mentioned abovefor polymer P48a.

Example 15

Preparation of P49a (u=97.5 mole %, v=2.5 mole %) using 2.5 mol %ED-2003. Diethyl succinate (DESucc, 1.14 g, 0.0066 mol),3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.93 g, 0.0064 mol), ED-2003(0.26 g, 0.00013 mol) and TBD (0.05 g, 0.00035 mol) were charged in aSchlenk tube. The reactants were mixed by simple vortex until miscible(1-2 minutes). The reaction was allowed to react at room temperature for4 hours and then the Schlenk tube was placed in a heated sand bath (80°C., 10 hours). Vacuum was applied to drive off the bi-product and shiftthe equilibrium towards product. The polymer I15 crystallized, limitingthe molecular weight.

Potential E′ and E″ end groups include those mentioned above for 114.

Intermediate polymer I15 was marginally soluble in DMF after heating to120° C. for 2-3 hours. Once dissolved and homogenous, the polymer wasquaternized (85° C., 24 hours) with benzyl bromide (2.5 g, 1.5 eq.). Thepolymer P49a was isolated by precipitation in THF. The polymer P49a(u=97.5 mole %, v=2.5 mole %) was rinsed 3 times with diethyl ether andfurther purified via dialysis. Mn (Aqueous GPC)=2,100 g/mol, PDI=1.75.FIG. 3 is a ¹H NMR spectrum of P49a.

Potential Z′ and Z″ end groups of P49a include those mentioned above forP48b.

Example 16

Preparation of P49b (u=97.5 mole %, v=2.5 mole %) using 10.0 mol %ED-2003. Diethyl succinate (1.25 g, 0.0072 mol),3,3′-diamino-N-methyldipropylamine (0.94 g, 0.0064 mol), ED-2003 (1.44g, 0.00072 mol) and TBD (0.05 g, 0.00035 mol) were charged in a Schlenktube. The reactants were mixed by simple vortex until miscible (1-2minutes). The reaction was allowed to react at room temperature for 4hours and then the Schlenk tube was placed in a heated sand bath (80°C., 10 hours). Vacuum was applied to drive off the bi-product and shiftthe equilibrium towards product. The polymer I16 crystallized, limitingthe molecular weight.

Potential E′ and E″ end groups of I16 include those mentioned above forP14.

Intermediate polymer I16 was marginally soluble in DMF after heating to120° C. for 2-3 hours. Once dissolved and homogenous, the polymer I16was quaternized (85° C., 24 hours) with benzyl bromide (2.2 g, 1.5 eq.).The polymer P49b was isolated by precipitation in THF. The polymer P49b(u=97.5 mole %, v=2.5 mole %) was rinsed 3 times with diethyl ether andfurther purified via dialysis. Mn (Aqueous GPC)=2,800 g/mol, PDI=1.69.FIG. 4 is a ¹H NMR spectrum of P49b.

Potential Z′ and Z″ end groups of P49b include those mentioned above forP48b.

Polymers P59a-f were prepared according to the following reactiondiagram, where subscripts u and v represent mole percentages. Subscriptsr, s, and t represent average degree of polymerization.

Example 17

Preparation of P59a (u=100 mole %, v=0 mole %, r>0, t>0, r+t˜6, s˜39,DP=19, RX=benzyl bromide) using 0 mol % ED-2003. Diethyl succinate(DESucc, 1.40 g, 0.0080 mol), 3,3′-bis(3-aminopropyl)piperazine (BAPPIP,1.61 g, 0.0080 mol), and TBD (0.05 g, 0.00035 mol) were charged in aSchlenk tube. The reactants were mixed by simple vortex until miscible(1-2 minutes). The reaction was allowed to react at room temperature for4 hours and then the Schlenk tube was placed in a heated sand bath (100°C., 1.5 hours) followed by heating at 150° C., 24 hours. Vacuum wasapplied to remove the alcohol byproduct and shift the equilibriumtowards product. The polymer I17 crystallized, limiting the molecularweight. Mn (GPC, DMF=5500 g/mol, PDI=1.20, u=100 mol %, v=0 mol %,degree of polymerization (DP)=19).

Intermediate polymer I18 was marginally soluble in DMF after heating to120° C. Once dissolved and homogenous, the polymer I17 was quaternized(85° C., 24 hours) with benzyl bromide (5 g, 3 eq.) Polymer P59a (u=100mole %, v=0 mole %, r>0, t>0, r+t˜6, s˜39, RX=benzyl bromide) wasisolated by precipitation in THF. The polymer P59a was rinsed 3 timeswith diethyl ether and further purified via dialysis.

Example 18

Preparation of P59b (u=100 mole %, v=0 mole %, r>0, t>0, r+t˜6, s˜39,DP=19, RX=methyl iodide) with 0 mol % ED-2003. Intermediate polymer I17was quaternized with MeI (4 g, 3 eq.) using the general proceduredescribed above for P59a.

Example 19

Preparation of P59c (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) with 2.5 mol % ED-2003. Diethyl succinate (DESucc,1.29 g, 0.0074 mol), ED-2003 (0.37 g, 0.00018 mol) and TBD (0.05 g,0.00035 mol) were charged in a Schlenk tube. The reactants were mixed bysimple vortex until miscible (1-2 minutes). The reaction was allowed toreact under nitrogen for 1 hour (100° C.).3,3′-Bis(3-aminopropyl)piperazine (1.45 g, 0.0082 mol) was charged inthe Schlenk tube was placed in a heated sand bath (150° C., 20 hours).Vacuum was applied to drive off the bi-product and shift the equilibriumtowards product. The intermediate polymer I19 crystallized, limiting themolecular weight. Mn (GPC, DMF=7500 g/mol, PDI=1.20; u=97.5 mol %, v=2.5mol % based on feed).

Intermediate polymer I19 was marginally soluble in DMF after heating to120° C. (2-3 hours). Once dissolved and homogenous, 119 was quaternized(85° C., 24 hours) with benzyl bromide (6 g, 3 eq.) The product polymerP59c (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39, RX=benzylbromide) was isolated by precipitation in THF. The polymer P59c wasrinsed 3 times with diethyl ether and further purified via dialysis.

Example 20

Preparation of P59d (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=methyl iodide) with 2.5 mol % ED-2003. Intermediate polymer I19 wasquaternized with MeI (5.6 g, 3 eq.) using the general proceduredescribed above to yield P59d.

Example 21

Preparation of P59e (u=95.0 mole %, v=5.0 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) with 5 mol % ED-2003. Diethyl succinate (DESucc, 1.05g, 0.0058 mol), ED-2003 (0.58 g, 0.00029 mol) and TBD (0.05 g, 0.00035mol) were charged in a Schlenk tube. The reactants were mixed by simplevortex until miscible (1-2 minutes). The reaction was allowed to reactunder nitrogen for 1 hour (100° C.). 3,3′-Bis(3-aminopropyl)piperazine(1.10 g, 0.0055 mol) was added to the Schlenk tube, and the Schlenk tubewas placed in a heated sand bath (150° C., 20 hours). Vacuum was appliedto drive off the bi-product and shift the equilibrium towards product.The polymer I21 crystallized, limiting the molecular weight.

Intermediate polymer I21 was marginally soluble in DMF after heating to120° C. (2-3 hours). Once dissolved and homogenous, 121 was quaternized(85° C., 24 hours) with benzyl bromide (2.6 g, 3 eq.). The polymer P59e(u=95.0 mole %, v=5.0 mole %, r>0, t>0, r+t˜6, s˜39, RX=benzyl bromide)was isolated by precipitation in THF. The polymer P59e was rinsed 3times with diethyl ether and further purified via dialysis.

Example 22

Preparation of P59f (u=95.0 mole %, v=5.0 mole %, r>0, t>0, r+t˜6, s˜39,RX=methyl iodide) with 5 mol % ED-2003. Intermediate polymer I21 wasquaternized with MeI (2.3 g, 3 eq.) using the general proceduredescribed above to form P59f.

The P60 series of polymers was made according to the following reactiondiagram, where subscripts u and v represent mole percentages andsubscripts r, s, and t represent average degree of polymerization.

Example 23

Preparation of P60a (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=methyl iodide) with 2.5 mol % ED-2003. Diethyl carbonate (DEC, 1.09g, 0.0089 mol), ED-2003 (0.46 g, 0.00023 mol) and TBD (0.05 g, 0.00035mol) were combined in a Schlenk tube. The reactants were mixed by simplevortex until miscible (1-2 minutes). The reaction was allowed to reactunder nitrogen for 1 hour (100° C.). 3,3′-Bis(3-aminopropyl)piperazine(1.45 g, 0.0082 mol) was added to the Schlenk tube, and the Schlenk tubewas placed in a heated sand bath (150° C., 20 hours). Vacuum was appliedto drive off the bi-product and shift the equilibrium towards product.The intermediate polymer I24 crystallized, limiting the molecularweight. Mn (GPC, DMF=8500 g/mol, PDI=broad and multimodal; u=97.5 mol %,v=2.5 mol % based on feed).

Intermediate polymer I23 was marginally soluble in DMF after heating to120° C. (2-3 hours). Once dissolved and homogenous, the polymer I24 wasquaternized (85° C., 24 hours) with methyl iodide (˜3 g, 2.5-3 eq.). Theproduct polymer P60a was isolated by precipitation in THF. The polymerP60a (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39, RX=methyliodide) was rinsed 3 times with diethyl ether and further purified viadialysis.

Example 24

Preparation of P60b with 2.5 mol % ED-2003. Intermediate polymer I23 wasquaternized with benzyl bromide using the general procedure describedabove for P60a (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide).

Polymers P73a-d were made according to the following reaction diagram,where subscripts u and v represent mole percentages and subscripts r, s,and t represent average degree of polymerization.

Example 25

Preparation of P73a (u=100 mole %, v=0 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) with 0 mol % ED-2003. Di-boc-guanidine (DBocG, 1.00g, 0.0038 mol), 3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.92 g,0.0038 mol) and TBD (0.05 g, 0.00035 mol) were combined in a Schlenktube. The reactants were mixed by simple vortex until miscible (1-2minutes). The reaction was allowed to react at room temperature for 4hours and then the Schlenk tube was placed in a heated sand bath (150°C., 10 hours). Vacuum was pulled to drive off the bi-product and shiftthe equilibrium towards product. The intermediate polymer I25 solidifiedas a rigid, solvent swollen gel, limiting the molecular weight.

Intermediate polymer I25 was soluble in DMF at room temperature. Oncedissolved and homogenous, 126 was quaternized (25° C., 24 hours) withbenzyl bromide (0.7 g, 1.0 eq.). The polymer P73a (u=100 mole %, v=0mole %, r>0, t>0, r+t˜6, s˜39, RX=benzyl bromide) was isolated byprecipitation in diethyl ether. The polymer P73a was rinsed 3 times withdiethyl ether and further purified via dialysis.

Example 26

Preparation of P73b (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) with 2.5 mol % ED-2003. Di-boc-guanidine (DBocG, 1.00g, 0.0038 mol), 3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.547 g,0.00376 mol), ED-2003 (0.193 g, 0.000096 mol) and TBD (0.05 g, 0.00035mol) were charged in a Schlenk tube. The reactants were mixed by simplevortex until miscible (1-2 minutes). The reaction was allowed to reactat room temperature for 4 hours and then the Schlenk tube was placed ina heated sand bath (150° C., 20 hours). Vacuum was applied to drive offthe bi-product and shift the equilibrium towards product. The polymerI26 solidified as a rigid, solvent swollen gel. The polymerizationbecomes diffusion controlled, limiting the molecular weight.

Intermediate polymer I26 was marginally soluble in DMF after heating to100° C. (30 minutes). Once dissolved and homogenous, 126 was quaternized(25° C., 24 hours) with benzyl bromide (0.6 g, 1.0 eq.). As the reactionproceeded it progressively became more homogeneous until solvated. Thepolymer P73b (u=97.5 mole %, v=2.5 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) was isolated by precipitation in THF. The polymerP73b was rinsed 3 times with diethyl ether and further purified viadialysis.

Example 27

Preparation of P73c (u=95.0 mole %, v=5.0 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) with 5.0 mol % ED-2003. Di-boc-guanidine (1.00 g,0.0038 mol), 3,3′-diamino-N-methyldipropylamine (DAMDPA, 0.53 g, 0.00366mol), ED-2003 (0.386 g, 0.000192 mol) and TBD (0.05 g, 0.00035 mol) werecharged in a Schlenk tube. The reactants were mixed by simple vortexuntil miscible (1-2 minutes). The reaction was allowed to react at roomtemperature for 4 hours and then the Schlenk tube was placed in a heatedsand bath (150° C., 20 hours). Vacuum was applied to drive off thebi-product and shift the equilibrium towards product. The polymer I27solidified as a rigid, solvent swollen gel. The polymerization becomesdiffusion controlled, limiting the molecular weight.

Intermediate polymer I27 was marginally soluble in DMF after heating to100° C. (30 minutes). Once dissolved and homogenous, 127 was quaternized(25° C., 24 hours) with benzyl bromide (0.6 g, 1 eq.). As the reactionproceeded it progressively became more homogeneous until solvated. Thepolymer P73c (u=95.0 mole %, v=5.0 mole %, r>0, t>0, r+t˜6, s˜39,RX=benzyl bromide) was isolated by precipitation in THF. The polymerP73c was rinsed 3 times with diethyl ether and further purified viadialysis.

Example 28

Preparation of P73d (u=90.0 mole %, v=10.0 mole %, r>0, t>0, r+t˜6,s˜39, RX=benzyl bromide) with 10.0 mol % ED-2003. Di-boc-guanidine(DBocG, 1.00 g, 0.0038 mol), 3,3′-diamino-N-methyldipropylamine (DAMDPA,0.50 g, 0.0034 mol), ED-2003 (0.772 g, 0.00038 mol), and TBD (0.05 g,0.00035 mol) were charged in a Schlenk tube. The reactants were mixed bysimple vortex until miscible (1-2 minutes). The reaction was allowed toreact at room temperature for 4 hours and then the Schlenk tube wasplaced in a heated sand bath (150° C., 20 hours). Vacuum was applied todrive off the bi-product and shift the equilibrium towards product. Thepolymer I28 solidified as a rigid, solvent swollen gel. Thepolymerization becomes diffusion controlled, limiting the molecularweight.

Intermediate polymer I28 was marginally soluble in DMF after heating to100° C. (30 minutes). Once dissolved and homogenous, the polymer I28 wasquaternized (25° C., 24 hours) with benzyl bromide. As the reactionproceeded it progressively became more homogeneous until solvated (0.6g, 1 eq.). The polymer P73d (u=95.0 mole %, v=5.0 mole %, r>0, t>0,r+t˜6, s˜39, RX=benzyl bromide) was isolated by precipitation in THF.The polymer P73d was rinsed 3 times with diethyl ether and furtherpurified via dialysis.

Table 2 summarizes the polymers formed.

TABLE 2 Amine Polymer Carbonyl Amine Monomer ED-2003 Example NameMonomer Monomer (mol %) (mol %) RX Mn PDI 1 P31a DMM MDEA 100 0 MeI 2P31b DMM MDEA 100 0 DMS 3 P31c DMM MDEA 100 0 BnBr 4 P31d DMM MDEA 100 0HexBr 5 P32a DMM DAMDPA 100 0 MeI 6 P32b DMM DAMDPA 100 0 DMS 7 P32c DMMDAMDPA 100 0 BnBr 8 P32d DMM DAMDPA 100 0 HexBr 1,020 1.19 9 P34a DMMBAPPIP 100 0 MeI 10 P34b DMM BAPPIP 100 0 DMS 11 P34c DMM BAPPIP 100 0BnBr 12 P38 DPC MDEA 100 0 MeI 13 P48a DESucc DAMDPA 100 0 BnBr 4,5102.19 14 P48b DESucc DAMDPA 95 5 BnBr 4,670 1.94 15 P49a DESucc DAMDPA97.5 2.5 BnBr 3,100 1.77 16 P49b DESucc DAMDPA 90 10 BnBr 2,270 1.88 17P59a DESucc BAPPIP 100 0 BnBr 1,740 1.89 18 P59b DESucc BAPPIP 100 0 MeI2,860 1.92 19 P59c DESucc BAPPIP 97.5 2.5 BnBr 3,510 1.89 20 P59d DESuccBAPPIP 97.5 2.5 MeI 3,000 1.67 21 P59e DESucc BAPPIP 95 5.0 BnBr 22 P59fDESucc BAPPIP 95 5.0 MeI 23 P60a DEC BAPPIP 97.5 2.5 MeI 24 P60b DECBAPPIP 97.5 2.5 BnBr 25 P73a DBocG DAMDPA 100 0 BnBr 26 P73b DBocGDAMDPA 97.5 2.5 BnBr 27 P73c DBocG DAMDPA 95 5 BnBr 28 P73d DBocG DAMDPA90 10 BnBr Minimum inhibitory concentration (MIC)

Bacterial samples were inoculated in TSB (or MHB) at 37° C., whereasfungi samples were inoculated in YMB (or MHB) at room temperature, bothunder constant shaking of 100 rpm (revolutions per minute). The sampleswere grown overnight to enter the log growth phase. A brothmicrodilution method was used to determine the respective MIC of eachpolymer, where 100 microliters of broth containing a polymer with aconstant de-ionized (DI) water content of 20% v/v at variousconcentrations was placed in each well of a 96-well culture plate. Priorto the addition of an equal volume of microbial solution into each well,the concentration of the microbial solution was first adjusted to obtainan optical density (O.D.) reading of approximately 0.07 at 600 nm usinga microplate reader (TECAN, Switzerland), which corresponds to theconcentration of McFarland 1 solution of 3×10⁸ colony forming units(CFU)/mL and followed by a 1000-time dilution to achieve an initialloading of 3×10⁵ CFU/mL. The 96-well plate was then incubated at 37° C.for bacterial samples and room temperature for fungi samples underconstant shaking of 100 rpm for 18 hours and 42 hours, respectively. MICwas regarded to be the least concentration where no observable microbialgrowth was detected by the microplate reader after the incubationduration. Broth containing only microbes was used as the negativecontrol. Six replicates were tested for each concentration of polymerand the control.

Killing Efficiency Test

The same procedure as described for MIC measurement was used todetermine the concentration of polymer that kills the microbes, and themicrobial samples were inoculated and prepared accordingly. Afterincubating for 18 hours for bacterial samples and 42 hours for fungisamples, wells containing polymers at various concentrations of 0.0MIC(0.0 times MIC), 0.5MIC (0.5×MIC), 1.0MIC (1.0×MIC), and 2.0MIC(2.0×MIC) were collected individually and diluted through a series oftenfold. The diluted microbial solution (20 microliters) was streakedonto an agar plate (LB Agar from 1st Base). The plates were thenincubated for 18 hours at 37° C. for bacterial samples and 42 hours atroom temperature for fungi samples. The colony-forming units on eachplate were counted.

Killing Kinetics Test

The same procedure as described for the killing efficiency test was usedto assess the duration time required for polymers to achieve 99.9killing efficiency of microbes. Eight duration times of 0, 0.25, 0.5, 1,2, 4, 8 and 18 hours were selected, and the microbes were treated at1.0MIC and 2.0MIC concentration of polymers.

For polymers P31a, P31c, P31a, P32a, P32b, P32d, P34a, P34b, P48a, P48b,P49a and P49b, TSB was used for all bacterial samples and YMB for fungisamples when assessing antimicrobial activities.

Hemolysis Assay

Fresh rat red blood cells (RBCs) suspension was diluted 25 times withPBS to achieve 4% v/v blood content. Polymers were dissolved in PBS atvarious concentrations with a constant DI water concentration of 20%v/v. Diluted blood suspension was treated with an equal volume ofpolymer solution and incubated at 37° C. for 1 hour. Aftercentrifugation of the mixtures at 1000 g-force for 5 minutes at 4° C.,100 microliters of supernatant was transferred into a 96-well cultureplate, with 4 replicates for each polymer concentration. The hemoglobinreleased was then measured using a microplate reader (TECAN,Switzerland) at 576 nm. Untreated RBCs suspension was used as thenegative control while RBCs suspension treated with 0.1% Triton-X wasthe positive control. Percentage of hemolysis was calculated as follows:Hemolysis (%)=[(O.D._(576 nm) of the treated sample−O.D._(576 nm) ofnegative control)/(O.D._(576 nm) of positive control−O.D._(576 nm) ofnegative control)]×100%In Vitro Cytotoxicity

Cytotoxicity of polymers was investigated by MTT assay, where HDF cellswere seeded on 96-well plates at a density of 10⁴ cells per well, andcultured in 100 microliters of DMEM supplemented with 10% FBS, 5%penicillin-streptomycin, 2 mM L-glutamine, 4.5 g/L D-glucose and 110mg/L sodium pyruvate, and incubated at 37° C., 5% CO₂ for 24 hours.Polymers were dissolved in the cell culture medium at variousconcentrations. The prepared solution (100 microliters) was then used tosubstitute the medium in each well. Each condition was tested in sixreplicates. The plates were then incubated at 37° C., 5% CO₂ for 6hours. After 6 hours of treatment with the polymer, 100 microliters offresh culture medium and 20 microliters of MTT solution (5 mg/mL) wereadded to replace the solution in each well. The plates were thenmaintained at 37° C., 5% CO₂ for 4 hours. Dimethyl sulfoxide (150microliters) was added to each well to dissolve the internalized purpleformazan crystals after removing the medium. The absorbance readings offormazan crystals were taken to be the absorbance at 550 nm subtractedby the absorbance at 690 nm (TECAN, Switzerland). Cell viability wasexpressed as a percentage of absorbance of the control cells without anytreatment.

Antimicrobial Activity

Antimicrobial activity of the polymers was assessed against fourdifferent microbes of clinical relevance: Staphylococcus aureus,Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Theminimum inhibitory concentrations (MICs) of all polymers were determinedusing the broth microdilution method, and were taken to be the lowestconcentration where no observable microbial growth was detected by themicroplate reader after the incubation duration with an initialmicrobial loading of 3×10⁵ CFU/mL. Toxicity of polymers was evaluatedvia the hemolysis assay with fresh rat red blood cells. Both MIC and 50%hemolysis (HC₅₀) values of the respective polymers are listed in Table3. Lower MIC and higher HC₅₀ values are desirable.

TABLE 3 Amine MIC (mg/L) Polymer Carbonyl Amine Monomer ED-2003 S. E. P.C. HC₅₀ Example Name Monomer Monomer (mol %) (mol %) RX Aureus ColiAeruginosa Albicans (mg/L) 1 P31a DMM MDEA 100 0 MeI >1000 >1000 >1000125 >1000 2 P31b DMM MDEA 100 0 DMS Not Determined 3 P31c DMM MDEA 100 0BnBr 500 (1000) 1000 >1000 500 >1000 4 P31d DMM MDEA 100 0 HexBr 500(1000) 1000 >1000 500 >1000 5 P32a DMM DAMDPA 100 0 MeI >1000 63 16125 >1000 6 P32b DMM DAMDPA 100 0 DMS >1000 125 31 500 >1000 7 P32c DMMDAMDPA 100 0 BnBr 16 8 63 125 >1000 8 P32d DMM DAMDPA 100 0 HexBr 8 8 31125 875 9 P34a DMM BAPPIP 100 0 MeI ≤4 16 16 500 >1000 10 P34b DMMBAPPIP 100 0 DMS 16 63 125 250 >1000 11 P34c DMM BAPPIP 100 0 BnBrInsoluble 12 P38 DPC MDEA 100 0 MeI Insoluble 13 P48a DESucc DAMDPA 1000 BnBr 31 8 16 250 >1000 14 P48b DESucc DAMDPA 95 5 BnBr 63 8 63250 >1000 15 P49a DESucc DAMDPA 97.5 2.5 BnBr 31 8 16 250 >1000 16 P49bDESucc DAMDPA 90 10 BnBr 63 8 31 250 >1000 17 P59a DESucc BAPPIP 100 0BnBr 31 16 31 125 >1250 18 P59b DESucc BAPPIP 100 0 MeI 8 63 8 63 >125019 P59c DESucc BAPPIP 97.5 2.5 BnBr 16 8 31 125 >1250 20 P59d DESuccBAPPIP 97.5 2.5 MeI 8 31 8 250 >1250 21 P59e DESucc BAPPIP 95 5.0 BnBr16 8 31 250 >1250 22 P59f DESucc BAPPIP 95 5.0 MeI 16 31 31 125 >1000 23P60a DEC BAPPIP 97.5 2.5 MeI 8 16 250 250 >1000 24 P60b* DEC BAPPIP 97.52.5 BnBr 63 125 250 250 375 25 P73a DBocG DAMDPA 100 0 BnBr 16 63 63250 >1250 26 P73b DBocG DAMDPA 97.5 2.5 BnBr 63 32 250 500 >1250 27 P73cDBocG DAMDPA 95 5 BnBr 125 63 250 500 >1250 28 P73d DBocG DAMDPA 90 10BnBr 63 63 500 500 >1250 *P60b was dissolved in DMSO (final DMSOconcentration in the test vial: 1% V/V).

Among the polymers of the 31, 32, 34 and 38 series, the MIC values forP32c and P32d were the lowest of all microbes tested, without inducingsignificant hemolytic effect or toxicity towards the red blood cells.The respective killing efficiency of both polymers on Gram-positive S.aureus, Gram-negative P. aeruginosa and fungi C. albicans was thenfurther evaluated. Using polymers P32c and P32d, each at a concentrationof MIC or 2.0MIC (2×MIC), at least 99.9% of bacteria were eradicatedafter 18 hours of incubation, and at least 99.9% of fungi wereeradicated after 42 hours, as illustrated in the bar graphs of FIG. 5(S. aureus), FIG. 6 (P. aeruginosa), and FIG. 7 (C. albicans). Thisresult was also obtained in the case of multidrug-resistant P.aeruginosa, indicating the effectiveness of the polymers. The durationneeded for the polymers to achieve 99.9% killing efficiency was alsoassessed using S. aureus as the model microbes. As shown in FIG. 8(overlapping pair of graphs), more than 50% of the bacteria were killedafter 30 minutes exposure to 2.0MIC concentration of polymers P32c andP32d. A killing efficiency of 99.9% was achieved within 4 hours and 2hours of treatment at MIC concentration and 2.0MIC, respectively. Basedon this trend, the duration is expected to further decrease at increasedconcentration of each polymer.

The respective MIC values of polymers P48a, P48b, P49a and P49b againstS. Aureus, E. Coli and P. Aeruginosa were similar to those of P32c andP32d. The presence of JEFFAMINE, even at 10 mol %, did not appear toreduce the antibacterial activity of polymers. P48a without JEFFAMINEand P49b with 10 mol % JEFFAMINE were selected to test for killingefficiency against S. aureus, P. Aeruginosa and C. albicans. The resultsare shown in FIG. 9 (series of bar graphs). The polyether chain ofJEFFAMINE did not weaken the effectiveness of polymer againstbacteria/fungi. At least 99.9% of bacteria and fungi were eliminatedafter 18 hours incubation at MIC and 2.0MIC concentrations.

Cell Viability

Through MTT assay, cytotoxicity of polymers P32c, P32d, P48a, P48b,P49a, and P49b was evaluated using the HDF cell line. The resulting cellviability is depicted in FIG. 10 (bar graph). Whereas P32c and P32d wereeffective against the microbes, they have shown to be toxic to thecells. Less than 80% cells remained viable after 6 hours of treatmentwith P32c at 31 mg/L, and with P32d at 16 mg/L. On the contrary, cellviability was clearly higher at these concentrations when the HDF cellswere treated with the P48 and P49 polymers prepared with JEFFAMINE. Inparticular, even at 1000 mg/L, more than 60% cells survived aftertreatment with P48b and P49b, indicating that the presence of JEFFAMINEsignificantly reduced the cytotoxicity of polymers, even at the highconcentrations. This result demonstrates that the biodegradablepolyamides are promising antimicrobial agents for use in consumer careproducts.

The polyamides of the 59 polymer series were similarly effective againstthe bacteria tested as compared to the polyamides of 48 and 49 series(P48a versus P59a, P49a versus P59c, P48b versus P59e). Polyamide P59dand polyurea P60a had low MIC values against E. coli, indicating thatthe urea groups in the backbone of the polymer might not adverselyaffect antimicrobial activity.

CONCLUSION

Antimicrobial polymers that were synthesized by condensationpolymerization and quaternized show excellent water-solubility andpotent antimicrobial activity against a panel of clinically relevantmicrobes including multi-drug resistant P. aeruginosa. The polymerscontain amide bonds that remain intact in aqueous solution, includingweakly alkaline environments, making them attractive for personal careproducts due to their longer shelf-life. On the other hand, the amidebond is enzymatically degradable, which avoids eco-toxicity. The use ofsuccinate monomer improved cell viability at comparable antimicrobialpotency relative to the 2-methylmalonate monomer (compare P48a with P32cin FIG. 10 at 250 mg/L concentration). Further improvement in cellviability at comparable antimicrobial potency was obtained by theintroduction of JEFFAMINE in an amount up to 10 mol % (compare P48a withP48b in FIG. 10 at 1000 mg/L concentration).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. When a range is used to express apossible value using two numerical limits X and Y (e.g., a concentrationof X ppm to Y ppm), unless otherwise stated the value can be X, Y, orany number between X and Y.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and their practical application, and toenable others of ordinary skill in the art to understand the invention.

What is claimed is:
 1. A cationic polymer, comprising: i) a cationicrepeat unit of formula (1):

wherein W′ is a single bond or a divalent linking group having astructure *—C(═O)-L′-*, wherein L′ is divalent radical comprising 1-20carbons and L′ is linked to carbon 1, nitrogen labeled 2 is designated atail and W′ is designated a head, L^(a) and L^(b) are independentdivalent hydrocarbon groups comprising 2-20 carbons, and Q′ is adivalent radical selected from group consisting of

wherein R^(a), R^(b), R^(c), R^(d), R^(e) are independent monovalenthydrocarbon groups comprising 1-20 carbons and each X⁻ is an independentnegative-charged counterion; and ii) a polymeric repeat unit of formula(8):

wherein nitrogen labeled 2 is designated a tail, W″ is designated ahead, W″ is a single bond or a divalent linking group having a structure*—C(═O)-L″-*, wherein L″ is divalent radical comprising 1-20 carbons andL″ is linked to carbonyl carbon 1, L^(c) and L^(d) are independentdivalent linking groups selected from the group consisting of a singlebond, and hydrocarbon groups comprising 1-6 carbons, and P′ is adivalent poly(alkylene oxide) chain; wherein the cationic repeat unitand the polymeric repeat unit are covalently linked in a head-to-tailarrangement.
 2. The cationic polymer of claim 1, wherein the cationicpolymer is a random copolymer.
 3. The cationic polymer of claim 1,wherein L′ is selected from the group consisting of methylene,1,2-ethylene, 1,1-ethylene, 1,3-propylene, 1,1-propylene, 1,4-butylene,1,1-butylene, 1,5-pentylene, and 1,1-pentylene.
 4. The cationic polymerof claim 1, wherein L″ is selected from the group consisting ofmethylene, 1,2-ethylene, 1,1-ethylene, 1,3-propylene, 1,1-propylene,1,4-butylene, 1,1-butylene, 1,5-pentylene, and 1,1-pentylene.
 5. Thecationic polymer of claim 1, wherein W′ is a single bond.
 6. Thecationic polymer of claim 1, wherein W′ is a *—C(═O)-L′-*.
 7. Thecationic polymer of claim 1, wherein W″ is a single bond.
 8. Thecationic polymer of claim 1, wherein W″ is a *—C(═O)-L″-*.
 9. Thecationic polymer of claim 1, wherein P′ is a block copolymer chaincomprising a poly(propylene oxide) block and a poly(ethylene oxide)block.
 10. The cationic polymer of claim 1, wherein the cationic polymercomprises the polymeric repeating units in an amount of more than 0 mol% to about 10 mol % based on total moles of repeating units of thecationic polymer.
 11. The cationic polymer of claim 1, wherein thecationic polymer comprises the polymeric repeating units in an amount ofabout 2.5 mol % to about 10 mol % based on total moles of repeatingunits of the cationic polymer.
 12. The cationic polymer of claim 1,wherein P′ is a triblock copolymer having a structure according toformula (9):

wherein r, s, and t represent degrees of polymerization of respectiveblocks of alkylene oxide repeat units enclosed in the brackets, and r,s, and t independently have average values greater than
 1. 13. Thecationic polymer of claim 1, wherein P′ has a number average molecularweight (Mn) of about 500 to about
 5000. 14. The cationic polymer ofclaim 1, wherein P′ has a number average molecular weight (Mn) of about1500 to about
 2500. 15. The cationic polymer of claim 1, wherein thepolymeric repeat unit has a structure in accordance with formula (10):

wherein L″ is a divalent group comprising 1-20 carbons, r, s, and trepresent average numbers of respective alkylene oxide repeat units, andr, s, and t independently have average values greater than
 1. 16. Thecationic polymer of claim 10, wherein s/(r+t) has a value of about 2 toabout
 12. 17. The cationic polymer of claim 1, wherein R^(a) is methyland R^(b) is benzyl.
 18. The cationic polymer of claim 1, wherein R^(c),R^(d), and R^(e) are independently selected from the group consisting ofmethyl and benzyl.
 19. The cationic polymer of claim 1, wherein L′ ismethylene.
 20. The cationic polymer of claim 1, wherein L′ is


21. The cationic polymer of claim 1, wherein L′ is


22. The cationic polymer of claim 1, wherein L″ is methylene.
 23. Thecationic polymer of claim 1, wherein L″ is


24. The cationic polymer of claim 1, wherein L″ is


25. A method of killing a microbe, comprising contacting the microbewith the cationic polymer of claim
 1. 26. The method of claim 25, wherethe microbe is selected from the group consisting of Gram-positivemicrobes, Gram-negative microbes, fungi, and combinations thereof. 27.An antimicrobial composition comprising the cationic polymer of claim 1and at least one other chemical component.
 28. The antimicrobialcomposition of claim 27, wherein the antimicrobial composition isselected from the group consisting of soaps, shampoos, skin lotions,skin creams, cosmetics, mouthwashes, wound care agents, deodorants,surface cleaning agents, and laundry detergents.
 29. The antimicrobialcomposition of claim 27, wherein the antimicrobial composition is toxicto a microbe selected from the group consisting of Gram-positivemicrobes, Gram-negative microbes, fungi, and combinations thereof.